Revenue from Contracts with Customers - Disaggregated Revenue (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Disaggregation of Revenue [Line Items]
Service fee and commission income	$ 9,815	$ 9,651
Extended Warranty | IWS | Vehicle service agreement fees
Disaggregation of Revenue [Line Items]
Service fee and commission income	4,479	4,389
Extended Warranty | IWS | GAP commissions
Disaggregation of Revenue [Line Items]
Service fee and commission income	258	192
Extended Warranty | Trinity | Maintenance support service fees
Disaggregation of Revenue [Line Items]
Service fee and commission income	1,968	2,973
Extended Warranty | Trinity | Warranty product commissions
Disaggregation of Revenue [Line Items]
Service fee and commission income	582	496
Extended Warranty | PWSC | Homebuilder warranty service fees
Disaggregation of Revenue [Line Items]
Service fee and commission income	1,423	1,427
Extended Warranty | PWSC | Homebuilder warranty commissions
Disaggregation of Revenue [Line Items]
Service fee and commission income	211	174
Extended Warranty | Geminus | Vehicle service agreement fees
Disaggregation of Revenue [Line Items]
Service fee and commission income	887	0
Extended Warranty | Geminus | GAP commissions
Disaggregation of Revenue [Line Items]
Service fee and commission income	$ 7	$ 0